[PATCH 4/6] box: use replicaset.vclock in replica join/subscribe

[Vladimir Davydov]

On Mon, Nov 26, 2018 at 08:54:58PM +0300, Konstantin Osipov wrote:
> * Vladimir Davydov <vdavydov.dev at gmail.com> [18/11/26 10:27]:
> > Again, this is something that was introduced by commit f2bccc18485d
> > ("Use WAL vclock instead of TX vclock in most places") without any
> > justification.
> > 
> > TX has its own copy of the current vclock - there's absolutely no need
> > to inquire it from the WAL thread. Actually, we already use TX local
> > vclock in box_process_vote(). No reason to treat join/subscribe any
> > different. Moreover, it's even harmful - there may be a gap at the end
> > of a WAL file, in which case WAL vclock will be slightly ahead of TX
> > vclock so that should a replica try to subscribe it would never finish
> > syncing, see #3830.
> 
> OK to push.

Pushed to 2.1